Renaming and renumbering

You can rename a network, and move its IPv4 addresses to another range, without setting anything up again. Old addresses keep working for a week, so a device that is offline meanwhile is not cut off.

What it is

A network’s name is a label. It shows in juist status and is how you name the network in commands. Renaming it changes nothing else.

Each device has an address in the network: an IPv4 address and an IPv6 address. Renumbering moves the IPv4 addresses, of every device or of one. You need it when the network’s range clashes with a LAN you use, or with another network on the same device. IPv6 addresses never change.

Both are changes to the membership log, the signed list of every change that every device checks (How juist works). An admin makes them, and every device follows. Where the quorum needs more than one admin, the change waits for the others (Several admins).

Renaming the network

1on an admin's device

juist network rename office

It prints renamed "home" to "office", and every device takes the new name.

Moving every device’s address

2on an admin's device

Move the whole network into a new range:

$ juist network renumber 10.7.0.0/22
move "home" from 198.18.36.0/22 to 10.7.0.0/22, old addresses until Fri 9 Oct 14:00? [y/N] y
moving to 10.7.0.0/22; old addresses until Fri 9 Oct 14:00

Each device keeps its place in the range where that is free: 198.18.36.2 becomes 10.7.0.2.

3on any device

Watch the move:

$ juist network
home
  IPv4          10.7.0.0/22, 198.18.36.0/22 until Fri 9 Oct 14:00
  IPv6          fd77:9359:d9fb::/48

MOVING  FROM         TO        OLD UNTIL
laptop  198.18.36.1  10.7.0.1  Fri 9 Oct 14:00
nas     198.18.36.2  10.7.0.2  Fri 9 Oct 14:00

juist devices shows each device’s new address, and the old one after it, as 10.7.0.2 (was 198.18.36.2).

Until the deadline, devices answer at both addresses. After it, only the new ones work.

Moving one device’s address

juist network renumber phone 10.7.0.9

This moves phone to 10.7.0.9, in the network’s own range. Its old address keeps working until the deadline, as above.

Retiring old addresses now

When every device has heard of the move, you need not wait for the deadline:

To …	run
move one device and retire its old address at once	`juist network renumber phone 10.7.0.9 --finish`
retire every old address now	`juist network renumber --finish`

--finish warns first: devices not told of the move yet lose the old address.

Good to know

Old IPv4 addresses keep working for 7 days by default. --for 12h or --for 14d sets another time; make it long enough for every device to come online once.
The deadline is fixed when the change is proposed. Where other admins approve it later, they see how much of it is left.
A device keeps one old address. Moving it again before the deadline drops the earlier old address at once, and juist warns about it.
Retired addresses stay held, so that no other device takes them, until a plain juist network renumber --finish.
The new range must have room for every device. juist warns when it overlaps a LAN of this host, or another network the device is in.
Configuration outside juist that names old addresses is not moved: update firewall rules, /etc/hosts entries and the like yourself.
With several networks on the device, name the network first: juist network renumber work 10.7.0.0/24, juist network rename work office.

If something goes wrong

You see	What to do
`juist status`: `no IPv4 on this host: …`	two networks here overlap; renumber one of them, as the hint says
`juist: 10.7.0.9 is taken by nas`	pick a free address
`juist: 10.7.0.9 is outside the network's range …`	pick one in the range `juist network` shows
`juist: the network predates renumbering`	once every device runs this version: `juist log upgrade`